Thermostat casing structure



" Feb. 26, 1957 R. F. GARNER 2,783,334

THERMOSTAT CASING STRUCTURE Filed Dec. 2'7, 1954 INVENTOR. Russel/E Garner HIS ATTORNEY.

United States Patent THERMOSTAT CASING STRUCTURE Russell F. Garner, Youngwood, Pa., assignor to Robertshaw-Fulton Controls Company, Greensburg, Pa., a corporation of Delaware Application December 27, 1954, Serial No. 477,901

9 Claims. (Cl. 200-140) This invention relates to casing structures for thermostats and more particularly to casing structures for electric thermostats.

In the past it has been customary to mount thermostatic devices in a single casing or enclosure. Thus, to replace or service a part of such a device, it is necessary to disassemble the entire mechanism. Since a skilled person is generally needed to accomplish such an operation, it is usually more economical to replace the entire thermostat than to attempt repairs.

The customary electric thermostat usually consists of a power element, a switch arm biased into engagement with the power element and a pair of contact terminals for the s itch arm. As a result of high cur-rent applications such as the starting of electric motors, the contact terminals or the switch arm is usually the first element to require replacement. Thus, if the switch arm and contact terminals could easily be replaced by a non-skilled person, repair cost in such a device could be greatly reduced. It has been proposed to improve an electric thermostat by producing an improved casing structure which will afford easy replacement of the major operating parts.

It is an object of this invention to produce a casing structure for an electric thermostat that will make repairs possible by a non-skilled person and thus reduce the cost of operation.

Another object of this invention is to facilitate assembly and disassembly of an electric thermostat by mounting the major operating parts in separate casing portions which are easily assembled to place the major operating parts in active position with respect to each other.',

Another object of this invention is to produce an improved casing structure that will have various useful applications.

In the preferred embodiment of this invention, a power element or thermostatic regulator is mounted in one casing structure, a switch arm in a second casing structure and contact terminals for said switch arm in a third casing structure and means is provided to detachably connect said second and third casing structures to said first casing structure.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawing wherein an exploded fragmentary perspective view of a casing structure for a thermostat is shown.

Referring more particularly to the drawing, a first supporting structure 10, having side walls12, 1'4, an'end wall 16, a top wall 18, and a bottom and end thereof open, is adapted to mount a thermostatic regulator within. A raised portion 20 on the top wall 18 is adapted to mount a bracket 22 which provides a means for attaching the supporting structure to a suitable structure.

The thermostatic regulator comprises an expansible and contractable diaphragm element 24, in communication with a capillary tube 26 which extends exteriorly of the casing structure 10 for communication with the usual temperature sensing bulb element 28. Thermostaticiregtu 2,783,334 Patented Feb. 26, 1957 lators of the described type are well known in the art and further description is unnecessary.

The diaphragm element 24 includes the usual movable member 30 and fixed end (not shown). The fixed end is carried on the inner end of an adjusting screw 32. The adjusting screw 32 is threaded within the bushing 34 and has an exterior and projecting from the casing structure It to carry the usual knob 36 by means of which the adjusting screw 32 can be rotated to change the position of the diaphragm 24 with respect to the supporting structure 10.

A slot 38 is cut in the side wall 14 to permit removal of the diaphragm 24 and the capillary tube 26. A screw 40 is threaded into the top wall 18 to fix a portion of the capillary tube 26 to the supporting structure 10 by means of a clamp 42. The threaded holes 44 in the top Wall 18 and two recesses 46 in the end Wall 16 are provided to facilitate attachment of supporting structures later to be described to the supporting structure 10.

A second supporting structure 48 of channel shape having side walls 50, 52 and a bottom wall 54. is adapted to mount a switch arm 56 which has a conducting element 58 pivoted on an end thereof. The switch arm 56 is pivoted in oppositely disposed recesses 60 in the side walls 50, 52 and afforded snap action by a pair of springs 62 acting in cooperation with a lever 64 which is pivoted on the side walls 50, 52 and connected to the switch arm 56 by the springs 62. Snap acting mechanisms of this type are Well known in the art and further description is unnecessary.

The second supporting structure 48 is adapted to be detachably secured in an active position with respect to the first supporting structure 10, whereby the bottom wall 54 will provide a bottom wall for the first supporting structure 10 and the outer surfaces of the side walls 50, 52 will be in engagement with the inner surfaces of the side walls 12, 14. The side walls 50, 52 each have a tongue 66 projecting from an end thereof, which are adapted to be detachably received by the recesses 46. The bottom wall 54 is provided with two holes 68 which become aligned with the threaded holes 44 when the second supporting structure 48 is placed in an active position with respect to the first supporting structure 10.

When the second supporting structure 48 is in the abovedescribed active position with respect to the first supporting structure 10, the lever 64 will be engageable by the movable member 30 to cause snap acting movement of the switch arm 56 in response to temperature variations. The springs 62 serve to bias the switch arm 56 and the lever 64 toward the open side of the second supporting structure 48 and toward the movable member 30 when the second supporting structure 48 is in an active position with respect to the first supporting structure 10. Thus, the lever 64 will move with the movable member 30 in response to temperature variations.

To restrict movement of the switch arm 56 under the bias of the springs 62 when the second supporting structure 48 is not in an active position with respect to the first support-ing structure 10, a barrier 70 is loosely mounted across the top of the second supporting structure 48 having the ends thereof in oppositely disposed recesses 72 in the side walls 50, 52. Thus, when the second supporting structure 48 is not in an active position with respect to the other supporting structures, the switch arm 56 will engage the barrier 70.

A third supporting structure 74 of non-conducting material has a hollow body portion 76 and a flanged end wall 78 which is adapted to provide an end wall for the main supporting structure 10 when the third supporting structure 74 is placed in an active position with respect to the first supporting structure 10 and the second supporting structure 48. The body portion 76 is adapted to engage'the inner surfaces of the side walls 50, 52 and the bottom wall 54 of the second supporting structure 48 and the top wall 18 of the first supporting structure when placed in an active position therewith. The flanged end wall 78 is adapted to overlap the ends ofthe side walls 50,52 and bottom wall 54 of the second supporting structure and side walls 12, 14 and top wall 10 of the first supporting structure when placed in an active position therewith. When in the described active position, the open end of the body portion 76 engages the barrier 70.

The third supporting structure 74 has an open chamber 80 within the hollow body portion 76. The chamber 80 is adapted to allow movement of the end of the switch arm 56 and its conducting element 58 within. Two conducting elements 82 are mounted within the third supporting structure 74 and have portions within the chamber 80 which define contact surfaces for the conducting element 58 of the switch arm 56 and portions projecting from the flanged face portion 78 to define two lugs which are adapted to be connected to an electric circuit.

Two holes 84 are spaced in the body portion 76 of the third supporting structure 74 and extend through the body portion 76. The holes 84 are positioned to become aligned with the holes 68 and the holes 44 when the third supporting structure 74 is placed in an active position with respect to the second supporting structure 48 and the first supporting structure 10. Each of the holes 84 in the body portion 76 is provided with arecess 86 at each end.

When the second supporting structure 48 and the third supporting strutcure 74 are placed in an active position with respect to the first supporting structure 10, screws 88 may be inserted into the holes 68 in the bottom Wall 54 of the second supporting structure 48 and through the holes 84 in the body portion of the third supporting structure 76 to be threaded within the top wall 18 of the first supporting structure 10. The screws 88 thus cooperate with the tongues 66 in the recesses 46 to hold the second supporting structure 48 and the third supporting structure 74 in an active position with the first supporting structure 10.

Operation It can be seen that when the second supporting structure 48 and the third supporting structure 74 are placed in an active position with respect to the first supporting structure 10, the lever 64 will be in a position to be engaged by the movable member 30. The conducting element 58 on the switch arm 56 will be normally engaging the contact surfaces of the conducting elements 82. Upon expansion of the diaphragm 24, the resulting movement of the lever 64 by the movable member 30 will cause the conducting element 58 to snap out of engagement with the contacting surfaces of the conducting element 58.

In the event of failure of a part in the device such as the switch arm 56 or the conducting elements 82, it is only necessary to replace the supporting structure containing the defective part. remove the screws 88 holding the supporting structures in their active positions with each other to remove any one supporting structure, an unskilled person can easily service the device by removing the supporting structure containing a faulty part and substituting a new one. This is one of the main features of this invention.

Although a preferred embodiment of this invention has been shown and described herein, it is to be understood that the invention is not limited to the details of construction and arrangement of parts disclosed but is to be interpreted as claimed.

It is claimed and desired to secure by Letters Patent:

1. In a casing structure for a thermostat having thermally responsive means, controlling means, and operating means for actuating the controlling means in response to variations in the temperature condition of the. ther mally responsive means, the combination comprising a Since it is only necessary to 4 main supporting structure for supporting the thermally responsive means, a second supporting structure for operating the operating means, a third supporting structure for supporting the controlling means, and means for detachably connecting said second and third supporting structures to said main supporting structure thereby placing said operating means in an operative position with respect to the thermally responsive means and with respect to the controlling means.

2. In a casing structure for a thermostat having thermally responsive means, switch means, and operating means for actuating the switch means between positions in response to variations in the temperature condition of the thermally responsive means, the combination comprising a main supporting structure of generally rectangular configuration for supporting the thermally responsive means and having a plurality of side walls, a second supporting structure of generally rectangular configuration for supporting the operating means and having a plurality of side walls, a plurality of tongues projecting from said side walls of said second supporting structure, said main supporting structure having a plurality of recesses in said side walls thereof for receiving said tongues to partially hold said second supporting structure in an active position with respect to said main supporting structure, a third supporting structure of generally rectangular configuration for supporting the switch means, the switch means being positioned to be actuated by the operating means when said third supporting structure is in an active position with respect to said second supporting structure, and means cooperable with tongues for holding said third supporting structure and said second supporting structure in an active position with respect to said main supporting structure.

3. In a casing structure for a thermostat having thermally responsive means, a switch arm engageable with the thermally responsive means and conducting elements engageable by the switch arm, the combination comprising a main supporting structure of generally rectangular configuration for supporting the thermally responsive means and having an open end and side, a second supporting structure of generally rectangular configuration for supporting the switch arm, means for detachably connecting said second structure to said main supporting structure to close said open side of said main supporting structure, means supported by said second structure for biasing the switch arm into engagement with the thermally responsive means when said second supporting structure is detachably connected to said main supporting structure, means within said second supporting structure for limiting movement of said switch arm by said biasing means when said second supporting structure is detached from said main supporting structure, a third supporting structure of generally rectangular configuration for supporting the conducting elements, means for detachably connecting said second structure to said main supporting structure to establish a closure for said open end of said main supporting structure, and to position the conducting elements in an operative position with respect to the switch arm, and means for holding said second and third supporting structures in an active position with respect to said main supporting structure wherein the switch arm is biased into engagement with thermally responsive means for movement therewith in response to temperature variations and the conducting elements are in a position to be engaged by the switch arm.

4. A casing structure for a thermostat as claimed in claim 3 wherein said movement limiting means comprises a barrier connecting the walls of said second supporting structure and positioned to be engaged by the switch arm.

5. A casing structure for a thermostat as claimed in claim 3 wherein said last named means comprises a plurality of tongues projecting from said second supporting structure, said main supporting structure having a plurality of recesses for receiving said tongues, and a screw extending through said second supporting structure and said third supporting structure and threaded within said main supporting structure.

6. In a casing structure, the combination comprising a first enclosure member of generally rectangular configuration having an adjacent end and side thereof open, a second enclosure member of generally rectangular configuration and having bottom and side Walls, said bottom wall beingadapted to provide a side wall for said first enclosure mmeber, said second enclosure member having tongues projecting from said side walls, said first enclosure member having recesses in an end wall to detachably receive said tongues and partially hold said first and second enclosure member in an active position, a third enclosure member of generally rectangular configuration and having an end portion thereof open, said third enclosure member being adapted to provide an end wall for said first enclosure member, and means cooperable with said tongues to hold said second enclosure member and said third enclosure member in an active position with respect to said first enclosure member.

7. In a casing structure, the combination comprising a first enclosure member of generally rectangular configuration having an adjacent end and side thereof open, said first enclosure member including an end wall having a plurality of recesses therein, a second enclosure member of generally rectangular configuration and adapted to provide a side wall for said first enclosure member thereby closing said open side thereof, said second enclosure member having a plurality of side walls and a plurality of tongues projecting from said side Walls, said tongues being adapted to be detachably received in said recesses to partially hold said second enclosure member in an active position with respect to said first enclosure member, a third enclosure member of generally rectangular configuration and having a side thereof open, said third enclosure member being adapted to provide an end wall for said first enclosure member when in an active position therewith, and means cooperable with said tongues to hold said second and third enclosure members in an active position with said first enclosure member.

8. In a casing structure, the combination comprising a first enclosure member of generally rectangular configuration and having a plurality of supporting walls and two adjacent sides thereof open, said first enclosure member having a plurality of recesses in one of said supporting walls, a second enclosure member of generally rectangular configuration and having a plurality of supporting walls, said supporting walls of said second enclosure member being adapted to engage the inner surfaces of said supporting walls of said first enclosure member, one of said supporting walls of said second enclosure member being adapted to close one of said open sides of said first enclosure member when said second enclosure member is in an active position with respect to said first enclosure member, a plurality of projecting tongues on said supporting walls of said second enclosure member, said projecting tongues being adapted to be detachably received in said recesses to partially hold said second enclosure member in an active position with respect to said first enclosure member, a third enclosure member of generally rectangular configuration and having a plurality of supporting walls, said supporting walls of said third enclosure member being adapted to engage the inner surfaces of said supporting walls of said first and second enclosure members, said third enclosure member having one supporting wall adapted to close said open side of said first enclosure member when said third enclosure member is in an active position with respect to said first enclosure member, and means cooperable with said tongues to hold said first, second and third enclosures in an active position.

9. A casing structure as claimed in claim 8 wherein said means comprises at least one screw extending through said second enclosure member and said third enclosure member and threaded into said first enclosure member.

References Cited in the file of this patent UNITED STATES PATENTS 1,072,009 Keefe Sept. 2, 1913 1,620,047 Van Valkenburg Mar. 8, 1927 1,641,265 Gaynor Sept. 6, 1927 1,944,687 Henderson Jan. 23, 1934 2,320,895 Sherlock et al June 1, 1943 

